Matt E., Sheila D., Jamie R., Terra H., Hang Y.

We updated our lockloss tool. A mistake of using the filter was fixed, and all filtering now is done by using secend order sections, which are more stable than using transfer functions ('BA') directly. The algorithm of handling invalid channel names when fetching data from the nds server (which was the time limiting part of our previous version) was also updated, such that now the lock loss analysis on all valid DQ channels can be finished in a few minutes. Besides the previous code finding all sudden changes before lock loss, Terra also finished a script that could pick out saturated channels. The codes are available at

/opt/rtcds/userapps/trunk/isc/common/scripts/lockloss

with both a python version and a matlab version.

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We applied the code to a lock loss happened at GPS time 1122945715.0, or UTC time 08/07/2015 01:21:38. The two plots shows the first 32 channels that glitched before this lock loss. In the plots, blue lines are raw time-ordered data streams of that channel, and red lines are absolute values of data filtered to a specific frequency band. Thin black lines are pop data, and thick vertical black lines indicate the starting point of that channel going wrong. In the two txt files, the one starts with lockloss shows all DQ channels that glitched for this lock loss, ordered by the time prior lock loss, and the one start with 'satLockloss' gives all channels that saturated.